BirdAnalyst
Species · BCR 33 · BBS 2025 Release · 1966–2024

Black-crowned Night Heron In Sonoran and Mojave Deserts

All regionsSonoran and Mojave DesertsWetland birds

Black-crowned Night Heron in Sonoran and Mojave Deserts has declined: down 42% on the route-weighted index since 1976.

-42%Since 1976TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →
12Routes In RegionSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
41YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable SignalsNotable signalsLong-arc shifts the engine flags automatically — sustained declines or increases large enough to stand out from year-to-year noise.Full methodology →

No notable trend signals for Black-crowned Night Heron in Sonoran and Mojave Deserts. See the full index history below.

Black-crowned Night Heron In Sonoran and Mojave Deserts Population Forecast

If the recent trend holds, Black-crowned Night Heron in Sonoran and Mojave Deserts is projected to fall about 78% by 2028 — from 0.17 in 2023 to a central estimate of 0.04 (95% range 0.00–0.30). A 5-year backtest shows a typical error of ±64.6%, with 100% of held-out values landing inside the 95% band.

-78%Change by 2028TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →
0.04Projected 2028 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.3095% range95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →
±64.6%Backtest errorBacktest errorTypical error when we hold out the most recent years, forecast them, and compare to what actually happened. Lower means a more trustworthy projection.Full methodology →
If the recent trend holds, Black-crowned Night Heron in Sonoran and Mojave Deserts is projected to fall about 78% by 2028 — from 0.17 in 2023 to a central estimate of 0.04 (95% range 0.00–0.30). A 5-year backtest shows a typical error of ±64.6%, with 100% of held-out values landing inside the 95% band.19732028
Projection of the recent trend (dashed) with 80/95% bands — a projection, not a prediction. Habitat, climate, and land use are not modeled.
YearProjected indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →95% low95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →95% high95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →
20240.050.000.32
20250.040.000.31
20260.040.000.31
20270.040.000.31
20280.040.000.30

Routes In Sonoran and Mojave Deserts

Routes recording Black-crowned Night Heron in Sonoran and Mojave Deserts.
Recent countThe raw number of individuals recorded on this route in its most recent survey year. A single-route tally, not a trend.Full methodology →
Palo Verde 2ARIZONA52023
Palo VerdeCALIFORNIA22013
LagunaARIZONA12011
Cibola LakeARIZONA12002
Palo VerdeARIZONA12012
ArabyARIZONA12011
Parker DamCALIFORNIA12003
NilandCALIFORNIA12019
Imperial DamCALIFORNIA12006
Lone PineCALIFORNIA11995
BrawleyCALIFORNIA12006
Ash MeadowsNEVADA12005

Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22.